Field of the Invention
The disclosure relates generally to devices and methods for driving a resistive random-access memory, and more particularly it relates to devices and methods of selecting a forming voltage for a resistive random-access memory.
Description of the Related Art
In integrated circuit (IC) devices, resistive random-access memory (RRAM) is an emerging technology for next-generation non-volatile memory devices. RRAM is a memory structure including an array of RRAM cells, each of which stores a bit of data according to resistance values, rather than electronic charge. In particular, each RRAM cell includes a resistive switching material layer, the resistance of which can be adjusted to represent logic “0” or logic “1.” RRAM devices operate under the principle that a dielectric, which has high resistance, can be switched to have low resistance through a conductive filament or conductive path formed therein after performing a forming operation with a sufficiently high voltage. The sufficiently high voltage is the ‘forming’ voltage.
The conductive filament or path can be formed through different mechanisms, including defects, metal migration, and other mechanisms. Various dielectric materials may be used in RRAM devices. Once the conductive filament or path has been formed therein, the RRAM device may be reset by breaking the conductive filament or path so as to be in a high resistance state, or set by reforming the conductive filament or path with an appropriately bias voltage so as to be in a low resistance state.
Due to process variation, the forming voltage for each of the resistive random-access memory cells varies considerably. Therefore, applied with a constant forming voltage may cause irreversible harm to some resistive random-access memory cells. For precisely providing an appropriate forming voltage to each of the resistive random-access memory cells, an effective device and method for driving a resistive random-access memory is required.